HP 3325A is a good synthesized function generator, with highly stable frequency. Sine wave production to 20 MHz; square wave production to 10 MHz. Triangle and tooth waveforms to 10 kHz.
Tek FG 504 operates up to 40 MHz but the frequency is not synthesized like the HP 3325A hence is not as stable. The sine, square and triangle waveforms in principle are all produced up to 40 MHz but in practice the waveforms don't look great at higher frequencies.
Remember that a function generator is not a substitute for a signal generator with respect to the following attributes:
- a signal generator typically offers AM, FM, PM, and maybe pulse modulation choices at minimum
- a quality signal generator will produce high quality modulated signals. When you look at the AM waveform with a spectrum analyzer you will see both sidebands have the same amplitude and the carrier does not decrease in amplitude relative to an unmodulated carrier. A lesser signal generator will show one sideband stronger than the other which indicates incidental FM on the waveform and/or may show carrier amplitude reduction at higher modulation percentages
- a quality signal generator has a calibrated attenuator down to - 130 dBm or better which you need when working on receiver front-ends. If you are using a function generator, the minimum output typically is 1 mV so you would need an external attenuator to bring down the signal level.
Good luck with your choice. You may end up with multiple signal and function generators as you gain experience with their use.
Patrick Wong AK6C
---In TekScopes@..., <kcrossett@...> wrote :
So does anyone have a good recommendation for a used function generator? I have been searching for a signal generator and have been saving my pennies for one, but I think a function generator may prove more beneficial since, as I understand it, a function generator has more waveform options.
